title: Stress cardiac magnetic resonance imaging provides effective cardiac risk reclassification in patients with known or suspected stable coronary artery disease.
abstract: BACKGROUND
  A recent large-scale clinical trial found that an initial invasive strategy does not improve cardiac outcomes beyond optimized medical therapy in patients with stable coronary artery disease. Novel methods to stratify at-risk patients may refine therapeutic decisions to improve outcomes.
  
  
  RESULTS
  In a cohort of 815 consecutive patients referred for evaluation of myocardial ischemia, we determined the net reclassification improvement of the risk of cardiac death or nonfatal myocardial infarction (major adverse cardiac events) incremental to clinical risk models, using guideline-based low (<1%), moderate (1% to 3%), and high (>3%) annual risk categories. In the whole cohort, inducible ischemia demonstrated a strong association with major adverse cardiac events (hazard ratio=14.66; P<0.0001) with low negative event rates of major adverse cardiac events and cardiac death (0.6% and 0.4%, respectively). This prognostic robustness was maintained in patients with previous coronary artery disease (hazard ratio=8.17; P<0.0001; 1.3% and 0.6%, respectively). Adding inducible ischemia to the multivariable clinical risk model (adjusted for age and previous coronary artery disease) improved discrimination of major adverse cardiac events (C statistic, 0.81-0.86; P=0.04; adjusted hazard ratio=7.37; P<0.0001) and reclassified 91.5% of patients at moderate pretest risk (65.7% to low risk; 25.8% to high risk) with corresponding changes in the observed event rates (0.3%/y and 4.9%/y for low and high risk posttest, respectively). Categorical net reclassification index was 0.229 (95% confidence interval, 0.063-0.391). Continuous net reclassification improvement was 1.11 (95% confidence interval, 0.81-1.39).
  
  
  CONCLUSIONS
  Stress cardiac magnetic resonance imaging effectively reclassifies patient risk beyond standard clinical variables, specifically in patients at moderate to high pretest clinical risk and in patients with previous coronary artery disease.
  
  
  BACKGROUND
  http://www.clinicaltrials.gov. Unique identifier: NCT01821924.
authors.affiliation: Noninvasive Cardiovascular Imaging Section, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors.forename: Ravi
authors.initials: R
authors.lastname: Shah
authors.forename: Bobak
authors.initials: B
authors.lastname: Heydari
authors.forename: Otavio
authors.initials: O
authors.lastname: Coelho-Filho
authors.forename: Venkatesh L
authors.initials: VL
authors.lastname: Murthy
authors.forename: Siddique
authors.initials: S
authors.lastname: Abbasi
authors.forename: Jiazhuo H
authors.initials: JH
authors.lastname: Feng
authors.forename: Michael
authors.initials: M
authors.lastname: Pencina
authors.forename: Tomas G
authors.initials: TG
authors.lastname: Neilan
authors.forename: Judith L
authors.initials: JL
authors.lastname: Meadows
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Francis
authors.forename: Ron
authors.initials: R
authors.lastname: Blankstein
authors.forename: Michael
authors.initials: M
authors.lastname: Steigner
authors.forename: Marcelo
authors.initials: M
authors.lastname: di Carli
authors.forename: Michael
authors.initials: M
authors.lastname: Jerosch-Herold
authors.forename: Raymond Y
authors.initials: RY
authors.lastname: Kwong
mesh_terms: D057791:Cardiac Imaging Techniques / Q000379:methods*; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000401:mortality*; D016757:Death, Sudden, Cardiac / Q000453:epidemiology; D018572:Disease-Free Survival; D005080:Exercise Test / Q000379:methods*; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000175:diagnosis / Q000401:mortality; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000401:mortality; D011379:Prognosis; D016016:Proportional Hazards Models; D018570:Risk Assessment / Q000145:classification / Q000379:methods; D012307:Risk Factors
keywords: chronic ischemia; magnetic resonance imaging